ZDive vs Fathom Dive Planner

ZDive transforms your Apple Watch into a smart dive companion with comprehensive iOS analytics. Whether you're snorkeling in tropical waters or logging recreational scuba dives, ZDive provides the tools you need for safe and memorable underwater adventures. APPLE WATCH — YOUR DIVE COMPANION Real-time dive tracking with automatic water submersion detection on Apple Watch Ultra (manual controls on other models) Rich sensor integration: depth, temperature, heart rate, compass, ambient pressure Scuba and snorkeling modes with Digital Crown navigation Industry-standard Bühlmann ZH-L16C decompression algorithm — the same model used by leading dive computers Real-time NDL calculations and safety stop monitoring Dive simulation mode: practice with realistic training scenarios Crash-safe recording: in-progress dives are checkpointed and automatically recovered GPS route tracking with breadcrumb trails Altitude diving support with automatic calibration Note: due to Apple's current API restrictions, live depth readings on Apple Watch are limited to about 6 meters. Deeper dives recorded with Apple's Depth app can be imported via HealthKit for full analysis. iOS APP — ADVANCED ANALYTICS & PLANNING Beautiful dive trends dashboard with period comparisons and personal records Interactive dive profile charts and sensor data visualization Diver profile with certifications and emergency contacts Import historical dives from Apple Health — duplicates are detected automatically Export dives in JSON and UDDF formats for other dive log software COMPREHENSIVE DIVE PLANNING SUITE Multi-Day Trip Planner with surface interval calculations Gas Planning Calculator: SAC rates, Nitrox optimizer, and a Trimix reference calculator Equipment Packing Lists with pre-built templates No-Decompression Planner with altitude compensation Interactive Decompression Tables: Bühlmann and PADI RDP PROFESSIONAL BREATHING TRAINER 10 breathing techniques: box breathing, 4-7-8, diaphragmatic Freediving-specific CO2 and O2 tolerance tables Wim Hof Method and tactical breathing patterns LIVE ACTIVITIES & WIDGETS Real-time tissue loading on Lock Screen and Dynamic Island No-fly time countdowns with maximum altitude restrictions Surface interval tracking between dives SAFETY & RELIABILITY 16-compartment tissue tracking with 6 conservatism levels Configurable safety stops (3–6 m depth, 3–7 minutes) Ascent rate monitoring with visual and haptic warnings Sensor data validation to filter spikes and false readings Automatic CloudKit backup and sync across devices Offline functionality with background synchronization SEAMLESS DATA MANAGEMENT Fast Watch-to-iPhone sync with optimized compression HealthKit integration for comprehensive health tracking Manual and automatic sync options with bulk import/export Try it instantly with a built-in demo dive — no gear required MULTI-LANGUAGE SUPPORT Available in English, Turkish, Chinese (Simplified), Russian, Spanish, Portuguese, Japanese, Arabic, French, Hindi, Bengali SUPPORTED DEVICES Apple Watch running watchOS 10.6 or later (Series 6 and later, SE, and Ultra) Apple Watch Ultra recommended: automatic submersion detection and enhanced diving sensors iPhone with iOS 17.6 or later, full iPad support for planning and analysis ZDive is free to use and supported by ads. Whether you're exploring coral reefs on a snorkel or logging recreational scuba dives, ZDive provides professional-grade planning and analysis tools in an intuitive interface. Note: ZDive is intended for recreational use as a dive companion and tracker, not as a certified dive computer. Always dive with certified diving equipment and follow proper safety protocols. Never rely solely on consumer devices for critical diving decisions. Join ZDive to enhance your underwater adventures. Dive deeper, plan smarter, and explore safely with ZDive.

Fathom is a native iPhone and iPad app for dive planning and logging. Build open- and closed-circuit decompression schedules with configurable gradient factors, then record every dive you make in the built-in logbook, and link each logged dive back to the plan that produced it. Build single- or multi-level dive plans, manage your gas mixes and tanks, and review every parameter that goes into your decompression schedule before you get in the water. After the dive, capture depth, time, gases, tanks, buddies, locations, and tags in a logbook designed for the same workflow. PLANNING • Configurable gradient factors (default GF 20/85) • Multi-level dive plans with automatic gas selection • Full trimix and heliox support, in addition to air and nitrox • Closed-circuit rebreather plans: fixed setpoints with a switch depth, and travel diluent for deep dives • Open-circuit bailout schedules computed from the worst point of the dive • Repetitive dives: tissue loading, CNS, and OTU carry across surface intervals • Custom gas mixes and standard preset catalogue • Tank and cylinder tracking with SAC and per-tank gas usage • Minimum gas (rock-bottom) reserve required to bring you and your buddy back from depth • NDL (no-decompression limit) at any depth • MOD, END, and gas density for every level, with warnings when a mix gets too dense • CNS clock and OTU oxygen exposure tracking LOGBOOK • Log every dive with depth, time, gases, tanks, location, buddies, and tags • Link each logged dive to its original plan • Browse and search your dive history GENERAL • Metric and imperial units throughout • iCloud sync across your iPhone, iPad, and Mac • One purchase unlocks Fathom on iPhone, iPad, and Mac IMPORTANT Fathom is a planning tool, not a substitute for diver training, qualified instruction, or the judgment of a certified dive professional. Always follow the procedures taught in your training agency, the limits of your certification, and your own dive computer. Decompression diving carries inherent risks. Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/